Multisite Cross‐Linked Ligand Suppressing Ion Migration for Efficient and Stable CsPbBr 3 Perovskite Quantum Dot‐Based Light‐Emitting Diodes

, representing the most efficient and stable perovskite LEDs based on cross-linked QDs. The improvement in device stability is attributed to the reduced ion migration, which is confirmed by analyzing the current behavior of QLEDs and time-of-flight secondary-ion mass spectrometry. This study provides a facile strategy for mitigating halide ion migration in perovskite fields toward more efficient and stable perovskite QLEDs.